In a response to four prominent US lawmakers voicing their concerns about ISPs' plans to monitor their customers' web usage for profit, AT&T has sent a letter attempting to justify its plans to step up its monitoring of users' surfing habits, taking the opportunity to attack Google's own policies at the same time.

In the letter, the company states that its current plans to monitor customers' net use is purely "for the purpose [of] developing a profile of a particular consumer's online behaviour," while saying it can usefully employ such methods in the future to assist detection of copyright infringement or detect child pornography.

"Even greater privacy concerns"

In comparison, says AT&T,Google "have evolved beyond merely tracking consumer web surfing activity on sites for which they have a direct ad-serving relationship. They now have the ability to observe a user's entire web browsing experience at a granular level, including all URLs visited, all searches, and actual page-views."

The ISP adds: "It even scans emails from non-Gmail subscribers sent to Gmail subscribers for contextual advertising purposes."

"If anything the largely invisible practices of ad-networks raise even greater privacy concerns than do the behavioral advertising techniques that ISPs could employ, such as deep-packet-inspection."